People who fit common criteria for Internet Addiction Disorder, or IAD, show changes in brain structure, according to a new study.
Analysis of MRI scans found that small regions of the IAD subjects’ brains had shrunk, in some cases by 10 to 20 percent. The affected areas were in the cortex, which is associated with high-level functions like processing speech, memory, emotion and sensory input.
Shrinkage was reportedly proportional to the duration of the subject’s online addiction, which suggests a causal link.
The scans also found increases and decreases in density to two deep brain structures, in areas tied to memory formation and decision making.
The Chinese-American study considered 18 college-age students who had IAD, according to a commonly used eight-question test and typically spent 10 hours per day, six days a week, playing online games. The control group was 18 “normal” Internet users who spent around two hours a day online.
“Our results suggested that long-term Internet addiction would result in brain structural alterations, which probably contributed to chronic dysfunction in subjects with IAD,” wrote the researchers in the study’s abstract.
The research makes a strong case for a link between structural brain changes and the lifestyle of extreme online gaming, and is reportedly the most rigorous study on the question to date.
It does not, however, answer questions about the health effects of those changes. One expert said that the shrinkage might be part of the normal pruning that brains undergo as people age, according to Scientific American.
In that sense it mirrors some research that has raised concerns about cell phone safety. For example, a recent study found that a cell phone held to the head caused glucose to migrate to that side of the brain. Whether or not that biological effect has health consequences remains unknown.
The IAD study evokes a 2006 study that found London taxi drivers had increased gray matter density in a brain region associated with spatial navigation and memory. The theory is that it’s the result of the cabbies memorizing the city’s 25,000 streets to pass “the Knowledge,” a famously difficult test required to get a taxi license.
IAD itself remains a controversial diagnosis, with experts differing on whether or not it’s a true addiction. The phenomenon of extreme online gaming is reportedly commonplace in China, with some 14 percent of young people playing to the point that it adversely affects the rest of their lives.